Appalling customer service and breach of contract

On 27/10/2015 I received a new iphone 6 on a 2 year contract from Vodacom Cavendish. I am a software consultant and rely heavily on my phone for skype, emails and internet connectivity<br> <br> 3 weeks after receiving the phone, the WIFI capability ceased to work after the battery ran flat. I returned the phone but was told they would have to send it away for repairs to Joburg and it would take at least 3 weeks. They offered to give me a replacement Samsung basic phone with no smart phone capabilities. I was going away on leave the following week and did not want to go on leave without a phone, albeit with no Wifi functionality. I was only able to return the phone in January. <br> <br> On 23/02/3016 I received a replacement iphone. When I got home and made a phone call, I discovered that the microphone did not work, and on closer inspection, I noticed an indentation on the phone. I returned it the next day and was told that they would have to send it away for a replacement. <br> <br> Currently I do not have a phone, and Tremaine will not take my calls. I am being billed for a product and service I do not have. Yesterday I received a text to say that I must pay R4800 to repair the faulty phone.<br>